1. Field of the Invention
The present invention relates to a portable information terminal device, and more particularly to a portable information terminal device with a built-in speaker for outputting audio information such as of music or the like.
2. Description of the Related Art
Attempts have been made in recent years to improve the performance, and also to reduce the size, of information processing devices such as personal computers or the like. There have been devised portable information terminal devices based on such attempts.
Some information processing devices such as personal computers or the like incorporate a built-in speaker for outputting audio information such as of music or the like, so that the information processing devices can output the audio information via the speaker.
In the information processing devices which can output the audio information via the speaker, the audio information is recorded in a built-in hard disk and output via the speaker, or a CD is inserted into a built-in CD player and the audio information recorded on the CD is output via the speaker. Alternatively, the audio information is distributed from a public network such as the Internet to the information processing device and output via the speaker, or the audio information is received from a radio station by the information processing device and output via the speaker.
If a portable information terminal device should incorporate a built-in speaker for outputting audio information, then it is necessary that the portable information terminal device be designed to meet the following requirements:
(1) In combining the speaker with a component of the portable information terminal device, the speaker needs to be mounted in the portable information terminal device at a position effective for its use and in a manner to keep the portable information terminal device portable.
(2) The portable information terminal device needs to be constructed for protection against resonance due to vibrations of the speaker and also in view of vibrations and shocks which the portable information terminal device suffer when carried by the user.
(3) It is necessary to reduce the entire size of the portable information terminal device to keep the portable information terminal device portable, and to increase the volume of a space where the speaker is placed in order to prevent a reduction in the quality of audio information such as of music or the like that is output via the speaker.
(4) The space where the speaker is placed needs to be hermetically sealed because if sound and air leaked out of that space, then the bass part of the audio information would not be reproduced well and noise would be produced by the leakage of air.